Using the supplied templates, the door openings were cut out the fuselage to fit the doors. This was an iterative process because the templates (flat) will not conform properly to the fuselage (compound curvature).
Using the canard template, the canard doghouse was cut out flush with the top of the canard bulkhead.
After the interior micro and tapes cured during a very nice Christmas break, it was time to finish the outside join line.
The duct tape was removed and the join area was sanded flush and smooth. Micro was smoothed on to fill and voids, followed by BID layups and peel ply along the entire perimeter. As well, the join along the roof and the firewall flange was sanded and bonded with layups.
With the fuselage halves clecoed, coarse accessory holes were cut where the door openings will be to provide access to the inside.
A vat of micro was prepared, as well as some BID layup tapes. The clecoes were removed and micro was applied to the top of the firewall flange. Duct tape was then applied to the exterior fuselage seam to prevent too much squish-out of micro. Clecoes were re-attached and micro was applied to fill the seam between the fuselage halves, smoothed, and covered with a layup.
The leftover flanges were trimmed from the top and bottom fuselage halves and all mating surfaces on both halves were sanded. The two halves were joined, aligned, and clecoed together.
After getting the top and bottom aligned and fixtures, the gap was less than 1/2″ all the way around.
I am trying to keep with the philosophy of doing as much as possible with the two fuselage halves before joining. A double layer of fine BID was placed around the periphery of the windows to provide more skin thickness for the interior trim to mount to. This was an excellent suggestion by Ron Stacy, who has shared many valuable build tips with me. The midline NACA air scoop was also fitted and glued in place.
Ron flew his beautiful Turbo XL into Georgetown Municipal (KGTU) for a very pleasant visit. We drove to Walburg for lunch at Dale’s Essenhaus, then back to my garage where Ron looked over my work. Ron provided a steady stream of excellent build tips. He has some implemented some interesting things on his aircraft, including cooling ducting on the bottom cowling and a special-purpose NACA duct for oil cooler and intercooler air.
Based on the flow modeling reported previously, I enlarged the NACA ducts by making them deeper by about 1 inch. This should deliver significantly more air to the plenum for cooling the engine and for use by the engine oil cooler. Disadvantages include a slight loss of headroom above the back seat.
Replaced the cheesy gearmotor-and-string contraption for aileron trim that came with the kit for an upgraded electric trim actuator. The factory sells this upgrade, which is a modified commercial linear actuator with an integral spring. This is very similar to the mechanism that Vance Atkinson devised and built for his Long-EZ. Very nice. It comes with a rod end that easily attaches to the aileron torque tube bell crank. Hard point installation is straightforward in the fuselage just aft of the whale tail and above the conduit.
My engine choice is currently a TSIO-550. I want to make sure that I have plenty of cooling air available to the engine and oil cooler. Recall that I am not electing to install an oil cooler in the nose of the aircraft.
I am planning to modify the factory-provided NACA ducts to enlarge the entrance height to 3.5″ and also allow for a 1/4″ thick airfoil lip at the duct entrance plane. I don’t really want to extend the length of the duct because of the headspace encroachment in the cabin. The concern is that the ramp angle for this configuration is about 9.6 degrees. This is higher than the recommended range from the old NACA literature.
To give myself some confidence, I ran some flow simulations in Solidworks and validated the performance of my modified NACA duct for takeoff conditions (0 MSL, 15C, 100 kts TAS) and medium cruise (10,000 MSL, -4C, 160 kts TAS). The unmodified (factory stock) duct provides 78% of free-stream mass flux and the enlarged entrance duct provides 77% of free-stream mass flux – only a tiny decrease in efficiency, but with a 1.75 times larger mass flow due to the enlarged area.
I hate doing things twice…. During landing gear retract testing, I discovered a small hydraulic fluid leak around the shaft end of the cylinder. Since I had replaced all the seals in the cylinder only a few months previous, I was curious to see what the issue was.
I removed the cylinder and took it apart, and on a very close inspection found that the seating surface for the poly-pak shaft seal had a raised area. Microscope inspection revealed that the very thin metal between the NPT tapped area for the fitting was pushed toward the seating surface and that there was a very small hole that was allowing hydraulic fluid to leak. No way to fix this – had to order a new end piece from the factory.
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